I have this code in php:

$route = parse_url($_SERVER['REQUEST_URI'], PHP_URL_PATH);

        switch ($route) {
            case '':
                echo "root";
                break;
            case '/':
                echo "root";
                break;
            case (preg_match("/^[a-zA-Z0-9-_] $/", $route) ? true : false):
                echo "db";
                break;
            default:
                header("HTTP/1.0 404 Not Found");
                http_response_code(404);
                print(http_response_code());
                break;
        }

The regexp has to match all routes containing alphanumeric characters and - and _. But it doesn't, instead all slips to the default option, 404.

Probably it is something wrong with the pregmatch inside the switch. Please help.

CodePudding user response：

There are few issues:

1. REQUEST_URI will return string with leading /, so you must add it in your regex: /^\/[a-zA-Z0-9-_] $/
2. switch checks if case value matches with provided value, so you should compare it with true instead of $route:

switch (true) {
    case $route == '':
        ...
    case $route == '/':
        ...
    case preg_match("/^\/[a-zA-Z0-9-_] $/", $route):
        ...
}

But in that case it's better to use simple if conditions:

if (empty($route) || $route == '/') {
    echo 'root';
    return; // Use early return in order not to jump to other cases
}

if (preg_match("/^\/[a-zA-Z0-9-_] $/", $route)) {
    echo 'db';
    return;
}


header("HTTP/1.0 404 Not Found");
http_response_code(404);
print(http_response_code());